The present invention relates to a gas- and liquid-tight fastener for connecting two contiguous edge portions of a material wall to be sealed, that is the material wall of an object, particularly such as containers, clothing articles, tarpaulins and/or the like, in which the edge portions of the material comprise at least one fastener which receives the locking forces, particularly a zipper or a spiral fastening, and locking members coordinated to each other which may be brought into a sealing position to each other when the fastener is being closed.
Gas- and liquid-tight fasteners are needed in many fields, e.g. in gas- and water-tight protective suits for the fire brigade, for gas protection and for civil defense, in water-tight clothing articles for diving, sailing and surfing, in water-tight packing materials of delicate and sensitive apparatuses, in tent roofs and tarpaulins, in rucksacks, bags and the like.
There are already known in the art fasteners intended for the above applications. For connecting contiguous edge portions of a material wall to be closed there are used zippers whose teeth are encircled by the edge portions of said material wall, and the tissue of the material wall is secured to the teeth of the zipper by means of metal clips. The free ends of the material wall are slightly projecting and then forced to sealingly fit against each other when the zipper is closed, so that the junction of the two edge portions is achieved by means of the zipper, and the sealing is achieved by means of the free ends of the textile material of the wall to be closed.
However, the disadvantage of such zipper system is that it is of very restricted tightness. In manufacturing the known zipper system, which may be performed only with the aid of special machines, there must be met close manufacturing tolerances because a tight sealing cannot be achieved anymore when for instance a clip arrangement is slightly offset. Moreover, due to the use of special machines the known fastener is expensive. Finally, such fastener is not elastic but comparatively rigid so that it is hardly suitable for clothing articles. The slider of the known zipper is hard to be actuated because it tightly encircles not only the teeth of the zipper but also the plastic-coated textile material surrounding said teeth and the clips holding the textile material together, whereby considerable frictional forces occur between the slider and the projecting sealing lips of the coated textile material and the clips. The zipper is further sensitive to kinking and exhibits a low transverse tensile strength. In the most unfavorable case it may happen that the retaining clips loosen or are distorted so that the coordination of the teeth to each other is changed, something that will result in leakages. It may also happen that the free ends of the material to be closed, which serve as locking members, gape when the fastener is distorted or twisted, so that also in such case the required tightness is not guaranteed anymore. However, exactly on use of the fastener in textiles the fastener is exposed to permanent tensile, pressure and/or bending loads so that the known fastener system is little suitable for this purpose. Another drawback lies in that the known fastener has a very thick outer surface and also for this reason produces an aesthetically unfavorable impression of the clothing articles and is further uncomfortable for the person who wears such articles.